VENTURI A specially shaped restriction in a tube
designed to speed up the flow of fluid passing
through in accordance with Bernoulli’s principle.
Venturis are used in carburetors and in many types
of fluid control devices to produce a pressure
drop proportional to the speed of the fluid passing
through them.

VENTURI EFFECT
The effect of Bernoulli’s
principle, which states that the pressure of a fluid
decreases as it is speeded up without losing or
gaining any energy from the outside.

VERIFIED Confirmation of information or configuration
status.

VERTICAL AXIS (YAW)
An imaginary line passing
vertically through the center of gravity of an
aircraft. The vertical axis is called the z-axis or the
yaw axis.

VERTICAL SPEED INDICATOR (VSI) An instrument
that uses static pressure to display a rate
of climb or descent in feet per minute. The VSI
can also sometimes be called a vertical velocity
indicator (VVI).

VERTIGO
A type of spatial disorientation caused
by the physical senses sending conflicting signals
to the brain. Vertigo is especially hazardous when
flying under conditions of poor visibility and may
cause pilot incapacitation, but may be minimized
by confidence in the indication of the flight instruments.

WAKE TURBULENCE Wingtip vortices that are
created when an aircraft generates lift. When an
aircraft generates lift, air spills over the wingtips
from the high pressure areas below the wings to the low pressure areas above them. This flow
causes rapidly rotating whirlpools of air called
wingtip vortices or wake turbulence.

WASHOUT
A condition in aircraft rigging in
which a wing is twisted so its angle of incidence is
less at the tip than at the root. Washout decreases
the lift the wing produces to improve the stall
characteristics of the wing.

WEATHER BRIEFING Means for pilots to gather
all information vital to the nature of the flight.
Most often obtained from FSS specialist.

WEATHERVANE
The tendency to point into the
wind.

WEIGHT
A measure of the heaviness of an object.
The force by which a body is attracted toward the
center of the Earth (or another celestial body) by
gravity. Weight is equal to the mass of the body
times the local value of gravitational acceleration.
One of the four main forces acting on an aircraft.
Equivalent to the actual weight of the aircraft. It
acts downward through the aircraft’s center of
gravity toward the center of the Earth. Weight opposes
lift.

WEIGHT-SHIFT CONTROL AIRCRAFT Powered
aircraft with a framed pivoting wing and a
fuselage controllable only in pitch and roll by the
pilot’s ability to change the aircraft’s center of
gravity with respect to the wing. Flight control of
the aircraft depends on the wing’s ability to flexibly
deform rather than the use of control surfaces.

WIND CORRECTION ANGLE Correction applied
to the course to establish a heading so that
track will coincide with course.

WIND DIRECTION INDICATORS
Indicators
that include a wind sock, wind tee, or tetrahedron.
Visual reference will determine wind direction and
runway in use.

WIND DRIFT CORRECTION
Correction applied
to the heading of the aircraft necessary to keep the
aircraft tracking over a desired track.

WIND SHEAR A sudden, drastic shift in windspeed,
direction, or both that may occur in the
horizontal or vertical plane.

WING A ram-air inflated and pressurized fabric
airfoil that produces the lift necessary to support
the powered parachute in flight; including the lines
that attach to the cart. Also called a parachute,
chute, or airfoil.

WING LOADING
The amount of weight that a
wing must support to provide lift.